1. Field of the Invention
The present invention relates to GSM telephone communications that use short message service (SMS) text messaging, and more particularly to the delivery of any SMS text after a call is ended and authenticating the source of the delivered text message with a logo or other graphic not forwardable by mobile phone subscribers.
2. Description of Background Information
The Short Message Service (SMS) defines sending and receiving mobile telephone text messages. SMS is part of the Global System for Mobile communications (GSM) digital standard. An SMS text can comprise of words or numbers or an alphanumeric combination for up to 160 characters of text in length using default GSM alphabet coding. SMS has become extremely popular because it can be used when voice is not the easiest or best communications medium. For example, it may be difficult or troublesome to listen to a voice call, jot down information at the same time and enter the information into the memory of the mobile phone. SMS provides an easy way to send information to a mobile phone subscriber and retrieve it later from the mobile telephone's local memory.
Apart from transmission of simple information, SMS is increasingly used as an advertising channel such as with a “Sponsored Call” service application. The Sponsored Call service provides a mobile phone subscriber an option to listen to a pre-recorded audio advertisement provided by a sponsor and to receive a portion of their call paid for by the sponsor. When the mobile phone subscriber chooses to listen to an audio message—typically an advertisement message, they may also simultaneously receive an SMS message relating to the audio message for future access to the same information. The SMS text message is displayed on the mobile phone and stored in the local phone memory.
The conventional Sponsored Call service has a few disadvantages. Although the Sponsored Call service integrates audio and SMS advertising, the accompanying SMS text message is automatically sent to the subscriber simultaneous with the audio advertisement message. Subscribers may be bothered by these unwanted SMS messages, and the advertising effect may therefore be reduced. Some of these SMS messages may contain discounts to products and services, e.g., electronic or mobile coupons (“m-coupons”). But offering m-coupons through SMS messages to every subscriber listening to the audio message, and allowing the SMS message to be easily forwarded to other subscribers, reduces the appeal and apparent worth of the m-coupons.